Back pressure valve



Nov. 1, 1960 .1. R. YANCEY BACK PRESSURE VALVE 2 Sheets-Sheet 1 FiledApril 23, 1958 INVENTOR JOHN R. YANCEY ATTORNEY Nov. 1, 1960 J. R.YANCEY BACK PRESSURE VALVE 2 Sheets-Sheet 2 Filed April 23, 1958 F'II3:El

INVENTOR JOHN R. YANCEY ATTORNEY ibs BACK PRESSURE VALVE John R. Yancey,Houston, Tex., assignor to Food Machinery and (Ihemical Corporation, SanJose, Calif, a corporation of Delaware Filed Apr. 23, 1958, Ser. No.730,423

s Qlaims. (Cl.137--612.1)

This invention pertains to well head equipment. More particularly theinvention relates to a back pressure valve adapted to be releasablyinstalled in a tubing string.

In certain well completion methods or other well operations that must beperformed under pressure conditions, as for example, washing operationsor in replacing the main cut-off valve of the Christmas tree, it isdesirable to install a back pressure valve in the upper end of thetubing string to prevent escape of the well fluids therefrom. The backpressure valve so installed must subsequently be removed from the tubingstring to permit the well to flow.

An object of the present invention is to provide a back pressure valvewhich may be run in or removed through the various assemblies of aChristmas tree, or through the blowout preventers of a recently drilledwell, and detachably locked in place in the upper end of a tubingstring.

Another object of the invention is to provide a back pressure valvewherein the pressures above and below the valve may be equalized priorto the disengagement of the valve assembly fromthe tubing string.

Another object of the invention is to provide a back pressure valvewhich may be released from, and reseated in, a tubing string withoutbeing removed from the Christmas tree.

These and other objects and advantages of the present invention willbecome apparent from the following description and accompanying drawingsin which:

Fig. 1 is a vertical section through a typical well head installationillustrating the back pressure valve of the present invention installedtherein, and the tool or sub used for installing and removing the backpressure valve.

Fig. 2 is an enlarged vertical section through the back pressure valveinstalled in a tubing hanger fixed to the upper end of a tubing string.

Fig. 3 is a partial vertical section through the back pressure valveshown in its released position and illustrating the connection betweenthe valve and the installing and removing sub.

Fig. 4 is a horizontal section taken on line 44 of Fig. 3 illustratingthe locking lugs in their retracted positions.

Fig. 5 is a similar section to that shown in Fig. 4 and illustrates thelocking lugs in their projected or locked positions.

Referring now to the drawings, Fig. 1 illustrates a well headinstallation comprising a tubing head 12 fixed to the upper end of thewell casing 14. A tubing hanger 16, frusto-conical in shape, isinstalled in the tubing head 12 and rests in a frusto-conical bowl 18formed in the upper portion thereof. The tubing hanger 16 is held in thebowl 18 by a plurality of hold-down bolts 20 threaded laterally into theupper flange portion 22 of the tubing head 12 so that their innerconical ends 24 abut a downwardly and outwardly beveled surface 26formed on the upper end of the tubing hanger 16. A tubing head adaptor30 is bolted to the upper end of the tubing head 12 by a plurality offastening members 32. Similarly, a master valve 34 is fastened to theupper end of the tubing head adaptor 30 by a plurality of fasteningmembers 35.

Patented Nov. 1, 1960 A flow controller 36 is fastened to the upper endof the master valve 34 by a plurality of fastening members 38.

The back pressure valve 40 of the instant invention is adapted to belocked within the tubing hanger 16 and is adapted to be installed andremoved by a sub 42 which is part of and extends downwardly from. a backpressure valve installing assembly 44 adapted to be releasably connected to the upper end of the flow control member 36 by aquick-disconnect type connector 46.

Referring now to Fig. 2, wherein the tubing hanger 16 is shown on anenlarged scale, the upper end of a tubing string 50 is threadedlyreceived in the lower end of the tubing hanger 16 by means of threads 52formed at the lower end of a bore 54 which extends through the hanger16. The bore 54 of the tubing hanger 16 is formed with an annular recess56 adapted to receive the locking lugs 58 of the back pressure valve 40.An annular upwardly facing internal shoulder 60 is formed in the bore 54below the annular recess 56 and is adapted to be contacted by adownwardly facing external shoulder 62 formed on the outer surface ofthe back pressure valve assembly 40.

Referring now to the back pressure valve assembly 40, per se, the valveassembly comprises a cylindrical housing 7 0 on which the previouslymentioned downwardly facing shoulder 62 is formed. A tubular mandrel 72is slidably received within the upper portion of the cylindrical housing70. The mandrel 72 comprises an upper cylindrical body portion 73slidably received within the bore of the housing, and a cylindricalextension 74- of reduced diameter projecting from the lower end of thebody portion 73 in axial alignment therewith. Whereas the upper andlower portions 73 and 74 of the mandrel 72 are rigid with each other,they are preferably sep-arably interconnected to facilitate assembly ofthe apparatus, threads 76 being employed to provide the desired rigidbut separable interconnection between the mandrel parts 73 and 74. Sincethe mandrel extension 74 is of smaller external diameter than the bodyportion 73 of the mandrel 72, the extension 74 is spaced from the innersurface of the tubular housing 70. The lower end of the mandrelextension 74 is provided with an outwardly extending boss 78, the outersurface of which is in sliding engagement with the inner surface of thehousing 70. Two annular grooves 80 are formed in the outer surface ofthe boss 78, and suitable O-ring seals 82 are mounted in the grooves 80and abut in sealing engagement with the inner surface of the housing 70.The O-rings 82 are spaced vertically from each other for purposes whichwill be described hereinbelow.

A sleeve is slidably mounted on the outer surface of the mandrelextension 74. The sleeve 90 comprises an upper portion 92 which is ofsuch thickness that the outer surface thereof is in sliding contact withthe inner surface of the cylindrical housing 74 The lower portion 94- isof thinner cross section and of lesser outside diameter, and is,therefore, normally spaced from the inner surface of the cylindricalhousing 70. A downwardly and inwardly tapered cam surface 96 connectsthe outer surfaces of the upper and lower portions 92 and 94,respectively, of the sleeve 90.

When the mandrel 72 is in its upper position relative to the housing 70,as illustrated in Fig. 3, the upper edge of the boss 78 abuts the lowerend of the sleeve 90 and the sleeve 90 is thus raised to a positionwherein the reduced diameter lower portion 4 thereof is adjacent theradially extending locking lugs 58 whereby the lugs 58 are permitted tomove inwardly so that their outer ends are within the outer confines ofthe housing 70.

An examination of the transverse sections illustrated in Figs. 4 and 5will show that, while the lugs 58 ap pear to be in opposed relation toeach other in the i1- lustration of Figs. 2 and 3 they are shown in thismanner for convenience only, and that the members 58 are actually threein number spaced at equal intervals of 120 around the housing 70. Whileit is preferred that three locking lugs spaced equally about theperiphery of the housing 70 be used, the particular number of lugs formsno part of the instant invention and the structure would be equallyoperative with a different number of lugs, for example, two or four,equally spaced about the periphery of the housing 70. The lugs 58 aremounted in suitable openings 101) formed in the housing 70 and areenlarged at their inner ends as indicated at 102 to limit the outwardmovement of the lugs 58 to prevent the lugs 58 from disengaging thehousing 70 through excessive outward movement with respect thereto. Theinward movement of the lugs 58 is controlled by abutment thereof withthe sleeve 90 mounted on the mandrel extension 74.

The movement of the mandrel 72 relative to the housing 70 is controlledby a pin 110 (Fig. 3) fixed to the mandrel 72 and extending outwardlytherefrom through a helical slot 112 formed in the housing 70. The sub42 is adapted to be releasably connected to the mandrel 72 by means of aconventional pin and J-slot connection wherein the pin 114 is formed onthe lower end of the sub 42 and is adapted to be received within theJ-slot 116 formed in the upper end of the mandrel 72.

A valve cage 120 is threaded to the lower end of the housing 70 asindicated at 122 and a valve seat assembly 124, provided with anoutwardly extending annular flange 126, is locked to the lower end ofthe housing 70 with the flange 126 clamped between the lower end of thehousing 70 and an upwardly facing shoulder 128 formed in the valve cage120. A ball valve 130 is slidably mounted within the cage 120 and isadapted to be pressed upwardly against the lower end of the valve seatassembly 124 by a compression spring 132' confined between the ball 130and the lower end 134 of the valve cage 120. As best seen in Fig. 1, aplurality of slots 136 are formed in the cage 120 to permit fluid fromthe tubing string 50 to enter into the cage 120 below the ball valve130, or conversely to permit fluid pumped downwardly through the valveassembly 40 to flow outwardly through the cage 120 into the tubingstring 50.

Immediately above the lower end of the housing 70 there is provided aplurality of radially extending pressure equalizing ports 140 whichextend through the housing 70 and provide communication between theexterior of said housing and an annular groove 142 formed on the innersurface thereof. As can be seen in Fig. 2 the previously describedO-ring seals 82 are adapted to be positioned one above and one below theannular groove 142 when the mandrel 72 is in its lower position relativeto the housing 70, thus sealing the ports 140 in the manner of a sleevevalve. A suitable ring seal 150 is mounted in a groove 152 formed in theouter surface of the housing 70 and is adapted to abut in sealingengagement with the inner surface of the tubing hanger 16 thus providingsuitable sealing between the outer surface of the housing 70 and thetubing hanger 16.

In the installation of the back pressure valve assembly 40, the mandrel72 is raised within the housing 70, and the lugs 58 are moved radiallyinward to their retracted positions illustrated in Fig. 3. The sub 42 isengaged in the J-slot 116 and the sub 42 is raised until the upper endof the housing 70 engages the lower end of a spacing member 160 (Fig. 1)on the valve installing assembly 44. The master valve 34 is closed andthe assembly 44 with the valve 40 connected thereto is installed on theupper end of the flow control member 36 by means of the connector 46.The valve 40 is now projecting downwardly within the flow control member36 and the upper portion of the valve housing of the master valve 34.The master valve 34 may now be safely opened, after which the sub 42 ismoved downwardly to move the valve 40 downwardly through the valve 34until the downwardly facing shoulder 62 on the outer surface of thehousing 70 abuts the upwardly facing shoulder 60 within the tubinghanger 16. The sub 42 is now rotated clockwise to disengage the pin 110on the mandrel 72 from its seat 162 at the upper end of the helical slot112 formed in the housing 70. The sub 42 is further lowered to move themandrel 72 downwardly within the housing 70 which is now supported onthe shoulder 61) within the tubing hanger 16. The downward movement ofthe mandrel 72 causes the lower end thereof to abut the upper end of thesleeve and move the sleeve downwardly so that the cam surface 96 thereonengages the lugs 58 and moves the lugs 58 outwardly into the annulargroove, or recess, 56 formed in the inner surface of the tubing hanger16. After the locking lugs 58 have been extended, further movement ofthe mandrel 72 causes the O-rings 82 to assume the position illustratedin Fig. 2, one above and one below the annular groove 142, thus closingthe radial pressure equalizing ports 140. When the valve assembly 40 isthus locked in place within the tubing hanger 16, the sub 42 isdisengaged from the J-slot 116 and removed. The desired washing stepsmay now be carried out, or the Christmas tree assembly may safely beremoved without danger of a blowout of the well fluids.

When it is desired to remove the valve 40 from the well, the sub 42 islowered through the master valve 34 and is engaged with the upper end ofthe mandrel 72 by means of the J-slot connection 114-116. The sub 42 canthen be used to raise the valve 40, as follows: upward movement of themandrel 72 initially moves the lowermost O-ring seal 82 above theannular groove 142 thus permitting well fluids from within the tubingstring 50 to enter the housing 70 through the ports 140 and equalize thepressure above and below the ball valve 130. Further upward movement ofthe mandrel 72 and the mandrel extension 74 fixed thereto causes theupper end of the boss 78 to abut the lower end of the sleeve 90, andcontinued upward movement of the mandrel 72 raises the sleeve 90 so thatthe smaller diameter lower portion 94 thereof is adjacent the lugs 58.When the pin reaches the upper end of the diagonal slot 112 the housing70 will commence upward movement, and the beveled upper edge of theannular recess 56 in the tubing head 16 will strike the beveled upperends of the lugs 58 and force the lugs inwardly to their retractedposition. When the valve assembly 40 has been raised far enough to clearthe master valve 34, the master valve 34 may be closed and the backpressure valve installing assembly 44 removed from the upper end of theflow control member 36 by disconnecting the connector 46. Thus it may beseen that whenever the valve 40 is released from its seat within thetubing head 12, the pin 110 is moved to the upper end of the slot 112and seats on the seat 162, whereby, the valve 40 is automaticallyconditioned so that it may be reseated in the tubing head without thenecessity of removing the valve from the Christmas tree. Thus, if thevalve 40 is raised until the upper end of the housing 70 contacts thelower end of the spacer sleeve 160, and it is found that the valve 40does not clear the master valve 34, the valve 40 may be reset in thetubing head 12 by again lowering and rotating the sub 12 in the mannerdescribed above, permitting the installing assembly 44 to be removed anda proper spacer inserted between the installing assembly 44 and the flowcontrol unit 36.

From the foregoing description it may be seen that a novel, eificient,releasable back pressure valve assembly has been provided which iscapable of being in stalled and removed from a well under pressurewithout danger of a blowout of the well fluids.

While a preferred embodiment of the present invention is describedherein it should be noted that various changes may be made thereinwithout departing from the spirit of the invention as defined in theappended claims.

Having thus described the invention, what I claim and desire to secureby Letters Patent is:

1. In a back pressure valve, a tubular housing, a tubular mandrelcomprising a body portion slidably mounted in said housing and anextension of reduced diameter projecting from the lower end thereof,means limiting longitudinal movement of said mandrel relative to saidhousing, a boss on the lower end of said mandrel extension, said bossbeing in sliding contact with the inner surface of said housing, sealingmembers mounted in vertically spaced apart relation on said boss anddisposed in sliding sealing engagement with the inner wall of saidhousing, a plurality of radial ports in said housing adapted to beclosed by said sealing members being positioned one above and one belowsaid ports when said mandrel extension is in its lowermost positionrelative to said housing, and a check valve assembly fixed to the lowerend of said housing and adapted to prevent upward flow of fluidtherethrough.

2. In a back pressure valve, a tubular housing, a tubular mandrelslidably mounted in said housing, said mandrel having a reduced externaldiameter lower portion, a boss on the lower end of said mandrel, saidboss being in sliding contact with the inner surface of said housing, aplurality of radial ports in said housing adapted to be closed by saidboss when said mandrel is in a lower position relative to said housing,a plurality of locking lugs mounted in said housing for radial movementwith respect thereto, cam means mounted on the reduced diameter portionof said mandrel for movement with said mandrel with respect to saidhousing, said cam means having a downwardly and inwardly tapered camsurface adapted to engage the lugs and project said lugs outwardly whensaid cam means is moved downwardly with respect to said housing, and acheck valve assembly fixed to the lower end of said housing and adaptedto prevent upward flow of fluid therethrough.

3. In a back pressure valve, a tubular housing, a tubular mandrelslidably mounted in said housing, said mandrel having a smaller externaldiameter lower portion, a boss on the lower end of said mandrel, saidboss being in sliding contact with the inner surface of said housing,sealing members mounted at vertically spaced points on said boss andadapted to abut in sealing engagement with the inner wall of saidhousing, a plurality of radial ports in said housing adapted to beclosed by said sealing members being positioned one above and one belowsaid ports when said mandrel extension is in its lowermost positionrelative to said housing, a plurality of locking lugs mounted in saidhousing for radial movement with respect thereto, cam means mounted onthe lower portion of said mandrel for limited movement with respectthereto between the lower end of the upper portion of said mandrel andthe upper end of said boss and for movement with said mandrel relativeto said housing, said cam means having a downwardly and inwardly taperedcam surface adapted to engage the lugs and project said lugs outwardlywhen said cam means is moved downwardly with respect to said housing,and a check valve assembly fixed to the lower end of said housing andadapted to prevent upward flow of fluid therethrough.

4. In a back pressure valve, a tubular housing, a tubular mandrel havinga body portion slidably mounted for longitudinal movement in saidhousing and a tubular extension of reduced diameter fixed to the lowerend of said body portion, means limiting longitudinal movement of saidmandrel relative to said housing, a boss on the lower end of saidmandrel extension, said boss being in sliding contact with the innersurface of said housing, a

pair of sealing members mounted at vertically spaced points on said bossand adapted to abut in sealing engagement with the inner wall of saidhousing, a plurality of radial ports in said housing adjacent the lowerend thereof and adapted to be closed by said sealing members beingpositioned one above and one below said ports when said mandrelextension is in its lowermost position relative to said housing, aplurality of locking lugs mounted in said housing for radial movementwtih respect thereto, cam means mounted on said mandrel extension forlimited movement with respect thereto between the lower end of the bodyportion of said mandrel and the upper end of said boss and for movementwith said mandrel relative to said housing, said cam means having adownwardly and inwardly tapered cam surface adapted to engage the innerends of said lugs and project them outwardly when said cam means ismoved downwardly with respect to said housing, and a check valveassembly fixed to the lower end of said housing and adapted to preventupward flow of fluid therethrough.

5. In a back pressure valve, a tubular housing, a tubular mandrel havinga body portion slidably mounted for longitudinal movement in saidhousing and a tubular extension of reduced external diameter fixed tothe lower end of said mandrel, means limiting the longitudinal movementof said mandrel relative to said housing, a boss on the lower end ofsaid mandrel extension, said boss being in sliding contact with theinner surface of said housing, a pair of sealing members mounted atvertically spaced points on said boss and adapted to abut in sealingengagement with the inner wall of said housing, a plurality of radialports in said housing adjacent the lower end thereof and adapted to beclosed by said sealing members being positioned one above and one belowsaid ports when said mandrel extension is in its lowermost positionrelative to said housing, a plurality of locking lugs mounted in saidhousing for radial movement with respect thereto, a cam sleeve slidablymounted on said mandrel extension for limited movement with respectthereto between the lower end of the body portion of said mandrel andthe upper end of said boss and for movement with said mandrel relativeto said housing, said cam sleeve having a downwardly and inwardlytapered cam surface adapted to engage the inner ends of said lugs andproject said lugs outwardly when said sleeve is moved downwardly withrespect to said housing, and a check valve assembly fixed to the lowerend of said housing and adapted to prevent upward flow of fluidtherethrough.

6. In a back pressure valve assembly, a tubular housing, a tubularmandrel slideably mounted in said housing, a plurality of locking lugsmounted in said housing for radial movement with respect thereto, cammeans mounted on said mandrel for limited movement with respect thereto,said cam means having a downwardly and inwardly tapered cam surfaceadapted to engage said lugs and project them outwardly when said cammeans is moved downward relatively to said housing, means for limitingthe movement of said cam means relative to said mandrel and defining alost motion connection permitting movement of said mandrel relative tosaid housing without movement of said cam means, and a check valveassembly fixed to the lower end of said housing and adapted to preventupward flow of fluid therethrough.

7. In a back pressure valve assembly, a tubular housing, a tubularmandrel slideably mounted in said housing, a plurality of ports in saidhousing, valve means connected with said mandrel and adapted to closesaid ports when said mandrel is in its lowermost position relative tosaid housing, a plurality of locking lugs mounted in said housing forradial movement with respect thereto, cam means mounted on said mandrelfor limited movement with respect thereto, said cam means having adownwardly and inwardly tapered cam surface adapted to engage said lugsand project them outwardly when said cam means is moved downwardrelatively to said housing, means for limiting the movement of said cammeans relative to said mandrel and defining a lost motion connectionpermitting movement of said mandrel relative to said housing to actuatesaid valve means without movement of said cam means, and a check valveassembly fixed to the lower end of said housing and adapted to preventupward flow of fluid therethrough.

8. In a back pressure valve assembly, a tubular housing, a tubularmandrel slidably mounted in said housing, a plurality of locking lugsmounted in said housing for radial movement with respect thereto, cammeans mounted on said mandrel for limited movement with respect thereto,said cam means having a downwardly and inwardly tapered cam surfaceadapted to engage said lugs and project them outwardly when said cammeans is moved downwardly relatively to said housing, means for limitingmovement of said cam means relative to said mandrel, and a check valveassembly fixed to the lower end of said housing and adapted to preventupward flow of fluid therethrough.

References Cited in the file of this patent UNITED STATES PATENTS

